Re: A simple Comparison

If you compare them using eq or ==, all you're doing is comparing their values as references. And since they're two different objects--ie. not references to the same object--they're two different references. So they won't be equal.

To do a proper object comparison, you'll need to write a method that compares two of your objects. One possibility would be to serialize the objects and compare the serialized strings:

    my $obj1 = new Obj;
    my $obj2 = new Obj;

    ## The two objects above are now equal, let's say.
    ## Serialize them, then compare the serialized
    ## data.

    use Storable qw/freeze/;
    if (freeze($obj1) eq freeze($obj2)) {
        ## They're the same.
    }
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In fact, you could even use overload to overload the comparison operator so that the proper comparison happens automagically:

    package Obj;
    use Storable qw/freeze/;
    use overload '==' => \&compare;

    sub compare { return freeze($_[0]) eq freeze($_[1]) }
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Now you can just say:

    if ($obj1 == $obj2) {
        # They're the same.
    }
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Re^2: A simple Comparison by njh@bandsman.co.uk (Acolyte) on Jul 24, 2015 at 14:19 UTC
This doesn't work if one or both of the objects is global, Storable::freeze will fail with "Can't store GLOB items".	[reply]
Re^3: A simple Comparison by choroba (Archbishop) on Jul 25, 2015 at 00:00 UTC
GLOB and "global" are two different things. You can easily freeze global variables, but you can't freeze typeglobs, see "Typeglobs and Filehandles" in perldata. `use Storable; bless our $x = [], 'My::class'; print Storable::freeze($x); # No error, $x is global. bless my $y = \*STDERR, 'My::class'; print Storable::freeze($y); # Can't store GLOB items, $y is le +xical.` [download] لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l]